[kvmtool,03/21] Copy 64-bit alignment attrtibutes from Linux 6.4-rc1

Commit Message

Oliver Upton May 26, 2023, 10:16 p.m. UTC

An update to vfio.h requires these macros.

Signed-off-by: Oliver Upton <[e-mail]>
---
 include/linux/types.h | 13 +++++++++++++
 1 file changed, 13 insertions(+)

Patch

diff --git a/include/linux/types.h b/include/linux/types.h
index 5e20f10f8830..652c33bf5c87 100644
--- a/include/linux/types.h
+++ b/include/linux/types.h
@@ -36,6 +36,19 @@  typedef __u32 __bitwise __be32;
 typedef __u64 __bitwise __le64;
 typedef __u64 __bitwise __be64;
 
+/*
+ * aligned_u64 should be used in defining kernel<->userspace ABIs to avoid
+ * common 32/64-bit compat problems.
+ * 64-bit values align to 4-byte boundaries on x86_32 (and possibly other
+ * architectures) and to 8-byte boundaries on 64-bit architectures.  The new
+ * aligned_64 type enforces 8-byte alignment so that structs containing
+ * aligned_64 values have the same alignment on 32-bit and 64-bit architectures.
+ * No conversions are necessary between 32-bit user-space and a 64-bit kernel.
+ */
+#define __aligned_u64 __u64 __attribute__((aligned(8)))
+#define __aligned_be64 __be64 __attribute__((aligned(8)))
+#define __aligned_le64 __le64 __attribute__((aligned(8)))
+
 struct list_head {
 	struct list_head *next, *prev;
 };